Correlative Assessment of Oenothera biennis L. Using In Vitro and In Ovo Models ^†

The combination of commercially available Oenothera biennis L. and Helianthus annuus L. oils (OBO-SFO) was evaluated in terms of oxidative stability and biological safety [1]. To assess the in vitro oxidative stability of the mixture, SFO was supplemented with OBO (100, 200, 300, and 500 ppm), respectively, with 200 ppm synthetic butylated hydroxytoluene (BHT), and stored for 30 days, during which peroxide value (PV), p-anisidine value (p-AV), and total oxidation value (TOTOX) were registered. The OBO-supplemented samples exhibited significantly lower PV, p-AV, and TOTOX levels than pure SFO throughout the storage period. Moreover, oxidative stability improved with higher OBO concentrations. The PV, p-AV, and TOTOX levels of SFO-OBO 500 ppm were comparable to those of the SFO-BHT 200 ppm combination, suggesting that 500 ppm OBO could match the preservative performance of the synthetic antioxidant in preventing lipid peroxidation in SFO. The in ovo biocompatibility and angiogenic effects were further examined using the hen’s egg chorioallantoic membrane assay. All of the tested samples were biocompatible and well-tolerated, with no signs of vascular irritation observed. Stereomicroscopic observation of CAM vascularization over 48 h after treatment with oil samples revealed that pure OBO caused a noticeable reduction in new blood vessel formation, whereas SFO did not alter the normal angiogenic pattern. Importantly, the SFO-OBO 500 ppm mixture supported an overall normal vascular development, showing only a mild decrease in vessel density. The SFO-BHT sample had a similarly minimal impact on the angiogenic process. The histological analysis of CAM tissues supported the previously observed findings, showing no structural damage following SFO-OBO 500 ppm treatment, except for a slight reduction in the number of vessels. In conclusion, the SFO-OBO combination delays oxidative degradation of SFO while maintaining excellent biocompatibility in ovo, suggesting that evening primrose oil could be a viable natural alternative to synthetic antioxidants for preserving sunflower oil-based products.